Determination of phonon deformation potentials and strain-shift coefficients in Ge-rich Si_{1− x} Ge _x using bulk Ge-rich Si_{1− x} Ge _x crystals and oil-immersion Raman spectroscopy

Abstract

The strain-free Raman shift of the Ge–Ge mode, , of Ge-rich Si1−xGex (x: Ge fraction) was determined accurately from the bulk Ge-rich Si1−xGex samples fabricated by the Czochralski (Cz) method. Using the obtained , the phonon deformation potentials (PDPs), p and q, and the strain-shift coefficient bLO of isotropic biaxial strained Ge-rich Si1−xGex thin films were extracted by oil-immersion Raman spectroscopy using Raman peak shifts of longitudinal and transverse optical (LO and TO) phonon modes. As a result, it was confirmed that these parameters are almost constant with small variations and that the strain-shift coefficient bLO is in good agreement with ab initio calculations. The parameters determined in this work are essential to realize accurate strain measurements using Raman spectroscopy for Ge-rich Si1−xGex devices.

Quantification of Ge fraction using local vibrational modes in Raman spectra of silicon germanium by oil-immersion Raman spectroscopy

“…On the other hand, we have already shown that the Ge-Ge mode for the Ge-rich SiGe thin film and confirmed no LVMs around the lower wavenumber side (260 ⩽ ω ⩽ 310) by oil-immersion Raman spectroscopy to determine the strain-shift coefficient and phonon deformation potentials in our previous study. 28) These results are in good agreement in ab initio calculations reported by Pagès and coworkers. 29) Pagès and coworkers have also reported the change in frequency or intensity of main (Si-Si, Si-Ge, and Ge-Ge) and minor (LVMs) Raman features by percolation/onedimensional-cluster scheme and ab initio calculations.…”

Local thermal conductivity properties of a SiGe nanowire observed by laser power sweep Raman spectroscopy

“…In this study, we only investigated Raman spectra for Ge-Ge vibration modes since the Raman spectral intensities of Si-Si and Si-Ge vibration modes were lower than that of Ge-Ge vibration modes as the SiGe NW is rich in Ge. In general, the Raman peak of the Ge-Ge vibration mode in the SiGe alloy is observed 31,36) at around the lower wavenumber side than 301 cm −1 . As shown in Fig.…”

Phonon dispersion of bulk Ge-rich SiGe: inelastic X-ray scattering studies

“…The spectrum consisted of three components. Considering the Raman spectra of pure Si, SiGe and Ge, 24,25) the peaks around 295, 405, and 460 cm −1 were assigned to the Ge-Ge, Si-Ge, and Si-Si modes, respectively. Each excitation peak intensity reflected the fraction of Si and Ge atoms.…”